Key Facts

Emergency anaesthesia is one of the most challenging aspects of anaesthetic practice. Time pressure, limited information, physiological instability, and the need for RSI create a high-risk environment. Structured assessment and team communication are critical.

Epidemiology

Approximately 30,000 emergency laparotomies are performed annually in England and Wales. NELA data shows 30-day mortality of ~9.6% and 1-year mortality of ~25%. Higher mortality is associated with increasing age, ASA grade, and delay to surgery. Emergency surgery accounts for approximately 11% of surgical procedures but 80% of surgical deaths.

Aetiology

Common emergency surgical conditions requiring anaesthesia:

• Abdominal: Bowel obstruction, perforation, appendicitis, ischaemic bowel, haemorrhage
• Trauma: Laparotomy, thoracotomy, orthopaedic fixation, neurosurgery
• Vascular: Ruptured AAA, acute limb ischaemia
• Obstetric: Emergency caesarean section, ectopic pregnancy
• Other: Necrotising fasciitis, testicular torsion, acute compartment syndrome

Pathophysiology

Emergency patients are often physiologically deranged: hypovolaemic, septic, acidotic, coagulopathic, or hypothermic. The stress response to both the disease process and surgery places extreme demands on the cardiovascular and respiratory systems. Anaesthetic agents cause further cardiovascular depression in already compromised patients.

Pre-Operative Assessment (Rapid)

• ABCDE approach: Simultaneous assessment and resuscitation
• Key information: Working diagnosis, allergies, medications, last meal, events leading to admission
• Risk stratification: NELA risk calculator, P-POSSUM, SORT
• Airway assessment: Often limited time — assume full stomach

Physiological Derangement

• Sepsis: Tachycardia, hypotension, fever/hypothermia, raised lactate
• Haemorrhage: Tachycardia, hypotension, pallor, falling Hb
• Obstruction: Dehydration, electrolyte imbalance, distension, aspiration risk
• Trauma: Multi-system injury, C-spine immobilisation, blood loss

Red Flags

• Lactate >4 mmol/L — tissue hypoperfusion, high mortality
• Predicted mortality >5% — trigger for consultant involvement and ICU booking
• Hypothermia <35°C + acidosis + coagulopathy — lethal triad
• Deteriorating consciousness — may indicate raised ICP, septic encephalopathy, or haemorrhage

Bedside

• ABG/VBG: pH, lactate, Hb, K⁺ — immediate results
• Point-of-care coagulation: TEG/ROTEM in major haemorrhage
• Blood glucose: Capillary
• ECG: Arrhythmia, ischaemia
• Urine output: Catheterise — assess perfusion

Bloods

• FBC: Hb, WCC, platelets
• U&Es: Renal function, K⁺ (hyperkalaemia risk with renal failure, massive transfusion)
• Coagulation: PT, APTT, fibrinogen
• Group and save / crossmatch: At least 2 units; activate major haemorrhage protocol if needed
• Lactate: Prognostic marker — serial monitoring

Imaging

• CT (trauma series): CT head, C-spine, chest, abdomen, pelvis
• CXR: Pneumoperitoneum, pleural pathology
• FAST scan: Focused Assessment with Sonography for Trauma — free fluid

Special Tests

• NELA risk calculator: Predicts 30-day mortality for emergency laparotomy
• P-POSSUM: Physiological and operative severity score
• SORT (Surgical Outcome Risk Tool): Predicts 30-day mortality

Non-pharmacological

• Team briefing: WHO checklist adapted for emergency; clear communication of plan
• Resuscitation before/during induction: IV access, fluid resuscitation, blood products
• Temperature management: Active warming from the outset — warm fluids, forced-air warmer, warm theatre
• Cell salvage: Consider for major blood loss cases

Pharmacological

• RSI: Standard for unfasted patients — propofol (reduced dose in shock) or ketamine (1-2mg/kg for haemodynamic stability) + rocuronium 1.2mg/kg
• Ketamine: Preferred induction agent in haemodynamically unstable patients
• Vasopressors: Phenylephrine 50-100mcg boluses; noradrenaline infusion if persistent hypotension; metaraminol 0.5-1mg boluses
• Major haemorrhage protocol: O-negative blood → crossmatch blood; 1:1:1 ratio of RBC:FFP:platelets; tranexamic acid 1g IV (within 3 hours — CRASH-2)
• Antibiotics: As per surgical team — administer before incision where possible

Surgical/Interventional

• Damage control surgery: Abbreviated surgery (control haemorrhage and contamination), then ICU resuscitation, planned return to theatre
• Interventional radiology: Embolisation for haemorrhage (pelvic fractures, GI bleeding)

Referral Criteria

• NELA mortality >5% — consultant surgeon and anaesthetist must be present
• NELA mortality >10% — ICU bed booked pre-operatively
• All emergency laparotomies — anaesthetic and surgical consultant notification

• NELA 30-day mortality: ~9.6% overall; ranges from 3% (low-risk) to >30% (highest risk)
• NELA 1-year mortality: ~25%
• Consultant involvement: Associated with lower mortality — NELA standards require consultant presence for high-risk cases
• Delay to surgery: Each hour delay beyond indicated time increases mortality
• Damage control approach: Improves survival in severely physiologically deranged patients

NELA Standards of Care

Induction Agent Selection in Emergency